Variable detention liquid treating apparatus



Aug. 11, 1953 w. J. HUGHES 2,648,632

VARIABLE DETENTION LIQUID TREATING APPARATUS 5'1. 15. 1947 4 Sheets-Sheet 1 IN VEN TOR.

1 1'7 WaZZen/Tfhgheq 953 w. J. HUGHES 2,648,632

VARIABLE DETENTION LIQUID TREATING APPARATUS Filed Aug. 13, 1947 4 Sheets-Sheet 2 60 84 4 6/ 66 61 w 62 3 M f 2 66 67 64 57 65 M I 7 I /5a /7 56 J7 1 INVENTOR.

BJVQZ rjfyhea,

Aug. 11, 1953 w. J. HUGHES 2,643,632

VARIABLE DETENTION LIQUID TREATING APPARATUS Filed Aug. 15, 1947 4 Sheets-Sheet 3 ii WE IN VEN TOR.

Aug. 1, 1953 w. J. HUGHES 2,648,632

VARIABLE DETENTION LIQUID TREATING APPARATUS Filed Aug. 13, 1947 4 Sheets-Sheet 4 IN V EN TOR.

Patented Aug. 11, 1953 VARIABLE DETENTION LIQUID TREATING APPARATUS Walter J. Hughes, Chicago, 111., assignor to Infilco Incorporated, Chicago, 111., a corporation of Delaware Application August 13, 1947, Serial No. 7 68,307

6 Claims.

This invention relates to an apparatus and method for treating liquid by what is known as the slurry process.

The apparatus and process of my invention can be applied to different phases of liquid treatment. It can, for example, as shown in Figures 1 to 3, be used for the flocculation, or coagulation, processes in which water is subjected to gentle agitation to flocculate solids therein. It can also be used, as shown in Figures 4 to 9, as a complete slurry type treating unit in which the solids formed in the treatment process are separated from the fluid medium.

One object of my invention is to provide an apparatusin which, and a process by which, the minimum detention time, as well as the average detention time, of liquid undergoing treatment can be accurately controlled, thus providing more efiicient utilization of the volume of the treating basin.

Another object :of my invention is to provide an apparatus which completely eliminates the danger of short circuiting of liquid undergoing treatment in the mixing zone in a slurry process in which the liquid, on an average, is recirculated many times.

Another object of my invention is to more accurately control the detention time of liquid undergoing treatment in a slurry treating process of the type described in my patents, Nos. 2,245,587 and 2,245,588.

A further object of this invention is to provide a slurry treating apparatus adapted for rectangular basins and which accurately proportions the recirculation as desired, and eliminates short circuiting of liquid undergoing treatment in the mixing zone.

A still further object of my inventioni to provide a slurry treating process and apparatus wherein the relative volume of the flows from the mixing zone to the clarification zone and the recirculation within the mixing zone may be separately and accurately controlled in order to adapt the slurry treating process to relatively large rectangular basins.

A still further object of my invention is to provide a flocculation, or coagulation, apparatus in which the amount and time of recirculation can be adjusted over a fairly Wide range of values and in which short circuiting is minimized.

A still further object of this invention is to provide a more thorough and rapid mixing of liquid high velocities and turbulence.

These and other objects of my invention will be apparent from the description and claims which follow.

Apparatus of the type described in my patents mentioned above has found wide acceptance in industrial and municipal treatment of water and However, such apparatus hereto-' other liquids. fore has been restricted practically to either round or square treating basins of considerable depth. In such equipment, a is Well known, the liquid undergoing treatment is, on the average, recirculated in the mixing zone a number of times and then passed into an intermediate level of a relatively quiescent clarification zone, an output quantity of water escaping from the slurry into a body of clear water in an upper part of the basin and the greater portion thereof being returned to the mixing zone for further treatment. For example, it is common to design this type of apparatus to provide about ten minutes detention time within the mixing zone and to turn over the content thereof at least once each minute, and to design the slurry flow passages and slurry holding space of the clarification zone so as to provide for complete recirculation in about five minutes, the amount of slurry so recirculated usually being about twice the output of treated water.

minimum.

I have found it advantageous to use a pressure chamber between the mixing zone and the slurry holding space so that the circulating slurry can be distributed uniformly throughout the length of an elongated treating basin. My discovery, however, goe beyond a mere pressure chamber as I have found that detention time can be reduced if the apparatus is designed so as to minimize short circuiting through the apparatus. I have also found that it is possible to design apparatus to provide for proper treatment of a variable water supply. In the past it was necessary to construct such equipment so as to provide a detention and rate of circulation sufficiently high to overcome the defects caused by short circuiting at the worst operating condition and to overtreat at all other times. I eliminate the possibility of short circuiting in the mixing zone, and thereby am enabled to reduce my total detention time; and also provide means whereby the detention time in the mixing zone can be varied over a wide range to fit variable conditions. The latter element is quite important, for in many installations the nature of the liquid varies ina manner which makes changes in detention in the treating chamber very desirable, and in those cases Such detention times are necessary in order to hold short circuiting to a 3 the detention time can be adjusted to meet such conditions. Such adjustment of the detention time not only permits use of smaller basins but makes operating more efiicient.

I have found that the factor of primary importance in determining the efficiency of the slurry type apparatus is the control of the minimum detention time,' or, what means the same thing, the control of short circuiting, and especially in the mixing Zone. To illustrate, assume that satisfactory results can be secured by five minutes detention in the mixing ior raction 'izone, but that it is possible for liquid to go through the zone and escape as partly treated Water in less than a minute, and that f a surncienn large amount of liquid will short circuit, when operating with five minutes detention, to upset operating conditions at times. In such a ca'se it may be necessary to enlarge the treating apparatus, and all the parts thereof, so as to provide a minimum detention of ten minutes and elongate the passageway 'iro'm' the mixing chamber to the clarification chamber so as to make the minimum time "two minutes, "or "slow" down the rate of throughput. Heretoiore such equipment has been designed to'provide anaverage detention time larg'er than"necessary in order to control shortj'circuiting within"reas-onable limits. The apparatus-and"process oi'iny invention are directed"to"theeliminatingfor "short'circuiting in thereaction'zone and"to"mal 'ing the total minimum andmaximum detention times'closer to the total" average detention time.

'Dne'advanta'ge of my invention, when applied toslurry type treatingplants, is in'tlie fact that it is p-rimarily 'designedfor' use in rather large rectangular basins, which"-is'*desirab'le in large installations. I' amalso able to control flows throughallportionsof such basins'so that each part of the apparatus is operating at maximum emciency. It is obvious that in apparatus of this"ftype, in which the entirerea'ction 'is compressed into a relatively short period, it is extremely ihiportahtto control fiow characteristics in. an; portions of the apparatuaas permissible output? is fiiiedhy the rate at'wh'ich treatment takes, place" at 'themost "inefficient point.

"Another'iiiip'ortaht advantage of my invention resides'intheiact that it provides very thorough mixing of the liquidbeing treated, thetreating reagent, ands'lurry in the. slurry process, in a very. short-time. and Without using. a high velocity flow or turbulentagitation. One of the essential requirements of eificientioperation of aslurry type liquid treating plant is the rapid and thorough'mixing of slur'ry, liquid to be treated and reageht 'as the reaction between the treating reagent and the. pre'c'ipitatable solids in the water must'ltakel place infthe presence of slurry. parti'cles. In. my. invention the water to be treated is intr du'ced'into one end of the mixing charliberj 'preferably' tangentially to a rolling cylindricalf body of slur'ry,and additional slurry is tangentially discharged at the surface of the rolling"bodyfofslurry throughout the length of the mixing chamber sothat the entering liquid is thoroughly rhixedwith the slurry by the time itreaches' the-other end of the mixing chamber.

when considered as a 'slurry type liquid treatingfap'paratus, my invention comprises a relativelylongrectangular treating basin with an elongatedhood'un thelowerpart thereof. The inlet-for'liquid to be -treated and the liquid moving"'-member"a're"at opposite ends in smaller equipment,whilein-large sizes I utilize two im 4 pellers, one at each end of the apparatus, and deliver the liquid into the center, thus providing two intercommunicating but functionally divided treating sections within a single tank. A floor under the hood divides the space thereunder in to a mixing zone and a pressure chamber. Slur-- ry passes from/the.pressurelchamber into=the rel atively zquiescent clartfication section Got the basin and also, and ordinarily a major part of the flow, returns directly into the mixing chainber. An important feature of my invention lies in the valvemieans by which the relative width ef-"the fiow passage from the pressure chamber back into the-mixing chamber can readily be variedt'o lcontrol the time taken for liquid entering to betreated to pass from the inlet to the pressure zone, i. e. pass through the mixing zone.

A broader'aspectof my invention, but insofar as apparatus is concerned a simpler one, relates to the more eflicient mixing of a reagent in water. The invention is applicable to any, such mixing but for purposes "of exeiniiiification will be ,;describedin connectidnniith the flocculation or impurities in a water treating plantby the addition of acoagulant such asaliiin. ""It isigenerah ly' assumed in 'theart thatflocculation-precoagulation, requires a p'eriddof fgen'tle stirring of. the water in order to providefor thorough mixing of the reagentthroughout the Waterand for repeated collisions'between the smalLr' newly formed precipitate, orcoagulum. In smalrflows thisis a rather simpleprocedure. Howeverfin largeflows of water, such asfin a, plant'adapted to treat millions of, gallonsiperday;ithe;proc'ess requires considerable apparatus and a basinof large size in order"toj'provide"'formixing overa prolonged period. This isdue to the?! fact that the stirring 'mustbeigentle,as' anyturbulence tends to break up the" newly"'for1ned; particles. However, it 'is difficult' to'mix asmall amount: of chemical with a large flow of water. without tur bulen'ce, but" turbulence is "destructive to fio'cs. To' overcome this"diinculty, itis customary to rapidly" andturbulently-mix the reagent .and'water in a' rapid mixing chamber; and'thedflocculate'the'precipitate'in alarge' basin providedwith gentle agitation means. Thus the basin used forfiocculation, -or"'coagulation, of liquids must usualiy'be"quitelarge' andmust'alsdbe provided with bafiiesor other expensivestructure which preventsphortcircuiting from inlet, to Toutlet. However, by the use of the invention herein-describ'ed I am-en'abled to thoroughly fioocizlat-impurities "in a flow 'of one-million gallons? pen-day in a'basin about-5* /2feet long,"8 *feet*wide and 41 feet deep; andto completely eliminate" the rapid'mi'xingstep.

The various aspects of my invention "will be readily understood from a?detai-led consideration of the drawin'gs'in which:

"Figurel is a longitudinal cress==secti'onal"view of a flocculation"or"coagulationfehamher of pne aspect of the" invention, witlrmotor removed, taken along 'the verti-c'at planes-indicated by-the line i i-'of Figure 3;

Figure 2 is a plan view oftheapparatusshown infFigure 1;

FigureSris a""'tran'sverse *c'ross=se'ctio-.nal view of'th'e apparatusshown in Figures 1' and' 'Z;

Figure 4 represents a, plan'viewiof a'-pr"eferred -emloodiment"ofiny invention when appl'iect'to-"a slurry type liquid treatingapparatus;

Figure 5 -is a transverse?vertical"oross sectigmal' view' of the apparatus taken at"the""'vertica1 plane indicated by thlin' ii 5 on Figure 4;

Figure 6 is a transverse, vertical cross-sectional view of the apparatus taken at the vertical plane indicated by the line 66 on Figure 4;

Figure 7 is a horizontal, cross-sectional view of the apparatus taken at the horizontal planes indicated by the line 7'| of Figure 6;

Figure 8 is a longitudinal cross-sectional view of the apparatus taken along the central axis, indicated by the line 88 in Figure 4.

Figure 9 is an enlarged view of a preferred type of liquid impeller particularly adapted for use in apparatus of this kind.

Referring first to the simple mixing apparatus shown in Figures 1 to 3, inclusive, I show a device eminently fitted for flocculation, or coagulation, of impurities in liquid. The apparatus comprises a relatively small basin l having side walls H and I2, ends |3 and I4 and afloor I5.

Along the side walls H and I2 are sharply sloping fills l6, which fill the corners so as to prevent deposit of solids therein. Likewise, longitudinally arranged along the center line of the fioor is a triangular shaped fill H which is adapted to prevent deposit of solids along the center line of the floor. As indicated above, a flocculation basin of this type can be approximately 5 feet long, 8 feet wide and about 5 feet deep, for fiocculating about one million gallons of water per day.

A diaphragm, or false floor, 20 is placed adjacent the top of the basin I0. In the size just mentioned this diaphragm would be about 4% feet above the fioor [5. This diaphragm, or partition, can be substantially horizontal, but ordinarily it slopes slightly toward the side walls H and I2, as shown, in order to avoid deposit of solids thereon. This partition divides the tank into a lower reaction zone B and a superposed pressure zone A. The diaphragm 20 terminates short of the side walls II and I2 to leave a fiow passage 2| along the side walls, as shown. A plurality of vertical baffles 22, perpendicular to the respective walls, are placed along the flow passages 2| in order to direct fiows through the passages 2| in a direction perpendicular to the axis of the tank. Associated with each passageway 2| is a valve plate 23, shown in the figures as resting upon the upper side of the diaphragm 29. The valve plate 23 is pivoted at a central point 2d, as shown, and is positioned by any suitable means, such as bell crank 25 actuated by rod 23. It is obvious that as the valve plates 23 are pivoted on their pivot points 24 they change the shape of the orifices 2| from a trapezoid with the large end adjacent one end wall, such as l3, to'a trapezoid with the larger end at the opposite end wall of the basin. This changing in the shape of the orifice is important in my invention as it permits regulation of circulation in the device to vary the length of time required for incoming water to be treated to pass through the lower zone, as will more fully be explained hereafter.

Also associated with the diaphragm 20 is a rotor casin 2'! located as near one end of the basin as possible. This rotor casing is in effect in an inverted truncated conical conduit, as shown in enlarged detail in Figure 9'. Operating within the rotor casing is a rotor 30 which is shown in detail in Figure 9. As there shown, the rotor preferably comprises a vertical shaft 3| to which is fixed a perpendicular plate 32 having a diameter substantially less than the major diameter of the rotor casing, as shown. On the underside of the plate 32 are afiixed a plurality (usually 12 or more) of impelling blades 33 which extend radially beyond the edge of the plate 32 gallons per minute.

tively small size.

Water to be treated enters through a raw water conduit 60 which branches into two dischargeoutlets 4|, one discharging on each side of the center line of the apparatus and in a direction:' perpendicular to the longitudinal axis. Chemical. inlets 42 introduce suitable treating reagent to the entering liquid to be treated. Treated water is withdrawn through an outlet pipe 43 which is; shown in these figures as leading from the lower: section of the basin l0, adjacent the rotor. It; can be mentioned that the location of the outlet; is not critical, for it can also be above the separating diaphragm 23 adjacent either end of the pressure zone. Location of the inlet for water and chemical is rather critical as it should be positioned as close to the end wall opposite the rotor as is possible, for the reasons hereafter explained.

During operation a lower reaction, or mixing, zone of the basin contains two functionally. separate, parallel and tangential cylindrical bodies of water having a spiraling motion from the inlet end of the basin to the opposite end at which the rotor is located, as indicated by the arrows in Figures 1 and 3,'although there is no structure to separate the two bodies. It will be noted that the raw water is preferably introduced at one end of the lower reaction chamber B in a direction tangential to the cylindrical bodies of water. As indicated above it will customarily be desired to recirculate liquid undergoing treatment through the basin a number of times and I have found that for many waters a recirculation of about five times is desirable.

volume of liquid from the lower reaction, or flocculation, chamber into the upper pressure cham- It will be noted that adjustment of the valve plates will not change the cross-sectional area of the orifices 2| but it will change theshapes of those orifices, and by changing the shape of the orifice I can vary the total time required for the entering liquid to be treated to pass through the mixing zone to and through the rotor 30.

This can perhaps be more readily understood if we divide the basin into five imaginary one foot sections, the section adjacent the inlet 4| being considered the first section. Assume that the valve plates are so positioned that the orifice 2| is rectangular. In that situation the crossj sectional area of the orifice for each sectionis Thus the rotor 30, driven by any suitable means not shown, pumps a large pipe 56 which is enclosed within the center fill ila extending along the longitudinal axis of the floor. The outlet pipe 56 is provided with a plurality of short horizontally extending orifice pipes 57, as is shown in Figures and 6 particularly. v

A hood structure 60 extends lengthwise in the lower portion of the basin. This structure can be made in any suitable manner but for purposes of illustration is shown as comprising sloping plates 6| and 62 extending from adjacent the lower edge of the sloping side walls 5|, inwardly and upwardly to adjacent the center of the tank. Preferably the lower edges of the plates 6i and 62 are provided with short skirts E53 and 64, respectively. The skirts and slopinghood are spaced a short distance from their respective side walls so as to provide passageways B5 and 66 from the space above to the space below the hood. The entire hood structure may be supported in any suitable manner in the basin, such as by gusset plates 61. At the top edges of the sloping plates 6| and 62 are vertical plates 68 and 69, respectively, which extend upwardly therefrom and terminate at a level below that of the weirs 55. These vertical plates form an inner passageway which extends upwardly from the upper portion of the hood 6!! and discharges adjacent but below the liquid surface as established by the weirs. Associated with the inner plates 68 and 69 are outer plates H and 12, respectively, which extend from above the liquid surface down to an elevation approximately that of the top of the hood 60, thereby forming outer flow passages 13 leading downwardly from the top of the inner passageway 10 and discharging downwardly over the top of the hood 65.

'Within the hood 69 is placed a partition, or dividing floor, 80 which divides the space under the hood into pressure chambers A (A and A") above the partition and mixing chambers B (B.

and B") below it. Circular openings 8| and 8la are located in the dividing floor, one adjacent each end wall Ma and [3a, respectively. Associated with the openings are the truncated rotor casings 21, which form short conduits or passageways between the reaction, or flocculation, chambers B and the pressure chambers A. Operating within the rotor casings are rotors 30, previously described. Rotation of the rotors 30, which is secured by any suitable means such as motors 93, provides pumping of a large volume of liquid from the mixin chambers B into the pressure chambers A at a relatively low head and velocity.

The upper portions of the pressure chambers A are in open communication with the inner passageway 10. It is preferred that a valving member, or plate, 82 be associated with the passageway !0, and so constructed and arranged as to permit variable settings from one end of the pressure chambers A to the other. A suitable valving member 82 is a rectangular plate suspended on tie rods 83 which are vertically adjustable by any suitable means, not shown.

The floor 80 of the pressure chambers A terminates short of the side walls BI and 62 of the hood (as shown in Figures 5 and 6) thereby pro viding outlets 84 and 85 at each side of the pressure chamber, both of Which discharge into the mixing and reaction chambers B. Preferably a plurality of transverse baffles 86 are associated,

with these outlets 84 and 85 in order to discharge liquid from the pressure. chambers A into the mixing chambers t ngentially to the rollin or spiraling, body of liquid in the mixing zone. Associated with the outlets 84 and 85 are valving plates 81 and 88, respectively. These valving plates 8'! and 88, as shown particularly in Figure '7, preferably extend from one hand of each pressure chamber to the other. Each valve plate is pivoted at any suitable point, such as 89, and is moved in a horizontal plane about its pivot point by any suitable means such as bell cranks 99 actuated by a rod 9|. It is desired that valve plates 81 and 88 be adjustable to provide outlets of varying width, and preferably outlets with a trapezoidal opening, varying linearly from one end of the chambers to the other, as described in connection with the first form of my apparatus.

In the form of apparatus shown in Figures 4 to 8 the liquid to be treated enters through an inlet pipe ME] which discharges into an inlet well Hill at the center of the tank. The inlet well lill is formed between walls I02 and I03 which extend upwardly from the partition, or false, floor 80 of the pressure chambers A to above the liquid level in the basin. The inlet well I01 preferably has two outlets I04 and |05 discharging adjacent the plates 6| and 82, respectively. It will be understood that approximately half of the flow through each outlet will go into the inlet end of the functionally separate mixing zones B and B". A deflecting bafile Hi6 divides the fiow from the conduit I00, so that approximately half of the flow goes through each of the passageways Hi4 and I05.

The necessary treating chemical'can be introduced at any desired point, such as through chemical feed line I Hi discharging into the influent pipe I00 (Figure 7), or through chemical feed line Ill discharging into the inlet well [0| (Figure 8), or feed lines such as H2 discharging into the pressure chamber A adjacent the rotors 30 or feed lines such as H3 discharging into the mixing chambers B (Figure 8). As is well known by those skilled in the art, the place of introduction of the treating reagent is often important and is determined-by the nature of the liquid to be treated, the type of treatment desired, and the nature of the reaction between the treating reagent and the liquid. Thus, in the clarification of a turbid Water by a coagulant, such as alum, the chemical is often added to the water before introduction into the treating basin, such as through chemical feed line H0 discharging into the infiuent pipe Hill. In a softening reaction it often is preferred. that the reagent, such as lime, be added in the mixing chambers B.

During operation the mixing chambers B, pressure chambers A, the passageways 84 and 85, and the lower portion of the outer clarification chambers C are filled with a slurry of liquid undergoing treatment and suspended solids collected and accumulated from previously treated liquid. As indicated above the operation for each half of the apparatus is the same, so, in order to simplify description of operation, I shall consider onehalf only (say the left end of Figure 8) and describe my invention accordingly. It will be understood that the mixing zone of my large apparatus is. divided functionally by the inlet well, so that, functionally, the single basin contains two units and operation is the same in both.

11 chambersC. .Such discharge is controlled by the positioning'of valve plate 82; and can be made by proper. adjustment of thisvalve, to providefona imiform. discharge throughout the length offlthe basin. In most instances a muchgreater proportion ,of the flow fromthe pressure. chamber A will be discharged through. the lateral outlets B4. and,-85 along the underside of the ho'odfiil. Such discharge, preferably at a velocity of about three feet per second, imparts a rolling motion to the. liquid inthe mixing chamber B, as indicatedbythearrowsin Figures and 6. Slurry is. pumped only, from one end. .of the reaction chamber B' into the pressure chamberA' andis introduced tangentiallyinto the reaction zoneB throughout its entire length, on both sides thereof, Such V introduction into, and withdrawal from, the. mixing chamber B, establishes two parallel spiraling, or rolling, bodies of liquid therein which bodies. extend fromoneend to the other. ,Liquid to be treated isintroducedthrough inlet well H! l likewisedischarging under. the hood tangentially to the rolling bodies of slurry. there: in,. thus assisting and maintaining the rolling motion'under the hood. Aswater to betreated isintroduced at one cnd and theslliiry With.- drawn from .the other, my apparatus provides maximum detention of. the water beingtreated inthe horizontally rolling spirals. andeliminates the possibility of an inadequate-detention the slurry.- While. it is possible for liquid undergoing treatment to pass directly through the high pressure chamber A, the passageways 1.0. andJ3, and

into the clarification space'C, it is impossible for.

the liquidentering to be treated to be shortcircuited in its passage through the chamber B; ;;I have discovered that detentian timein the mixing zone is a most critical element in slurry r a a d my a p a us is. d s gned to pic-- ventshort circuiting in this critical phase of'such processes. Thus the. introduction of the 'slprry into the, mixing chamberin a mannerto els'tab lish' a'rol'ling spiral throughoutthe length of the xin Cha e and th i tr ucin .qi iqu d to be treated at one end of thisrolling body, of

slurry and withdrawal of slurry fromthe opposite end of thespi ra1, is important .to .my' proces s. Due to'the iact that slurry is returnedfrqm the res e qhaimber. AT to he mixi g. hamber. B... tangentially throughout the length of the appar' ratus, it is impossible for entering liguidsto be short circuited from the inlet Well NH to the respective rotor. H

It will;be obvious, also, that valve plates 87 andts, .which' are, assqciatedwith the outlets Maud $5, affect thelengthof, retel tion in the chamber. These valve plates maybe set so as to provide a triangular openingwith its greatest width at the far end.(remot.e.from rotor...

30) ofthe pressure chamberA'. beset so as to provide a uniform .flow from the pressure chamber to the mixing Chamberthmugh out the length of the basin, the. wider setting. at

h y...clan a so' the far end of the chamber beingsuch. as to just overcome loss of head fromfriction and. other causes in the pressurechamber A. In.- those instances where maximum .detentionis desired the opening will be at maximum width adjacent the rotor. H An understanding of thesethings will probably be simplified by reference. toa particular water treating plant designed to treat 10 .volumes. of water per minute... As the fiow and treatment is equallydivided on the two sides ,of. the transverse.

,or is treated in each end. For purposes .9. mplific ationwe,wil1 consider only, such 5 gn te in. either end portion. .In this particular plant the rotor 30 was designed to pump 45,.units per; minute. o f water from the reaction zone B into the pressure chamber A, or nine times the il -p tt Three times the throughput, or 15 units per, min e, were passed from the pressure chamber-Ag into the clarification chamber C, of which 5.11 its weredischarged into the launder 53 and 10 units were returned into the mixing chamber 1.3 .through the. passageways and 66. Thirty linits of. slurry per minute were returned directly illie pressure chamber A into the mixing Qfiamber'B through the passageways 84 and 85. Inprdento illustrate the operation of my apparatus one can 1 imagine the mixing chamber di- Vided..into.5 longitudinal sections, Nos. 1 to .5, with"s'ec'tion, 1 being the section adjacent the inlet .endand section 5 being adjacent the rotor. In. thespecificexample discussed, the volume of the r ea ction zone A .yvaslOO units, or 20 units pe gsegtionfor four times the throughput flow perminute.

Example A Sections; 1 2. 3. .4..

Rein ed fromclarifi tionzbne O to inixm'g zone B'l Recirculation from press e zon A mixing'zone-B. .:c l 2 4 6 8 10 Total volume hi'o gh each section V (includilig' input) i' ';i. 9 15 23 33 45 Detention :time-imeach section (minutes) 2, 22 1. 33 87 61 4 t Total detention time, minutes." 5. 47

rambles Th e .ila1.ve;plates 81 .and 88 were set so as to proyide;a -uniformvv distribution throughout the lengthnf. th Pressure chamber. A. and the reactiqngqhamber ;B'..;The totaldetention time in this instance was 4.16 minutes, as follows:

ed m clarification zone C to I? mixing'zone B".; 2 2 2 2 2 Recirculatedrfrom pressure zone A to mixing zoneB n-ssuu 6 6 6. .6 6 Tote "olum"thro h each section (inclutlmg;input) u L1 L 13 21 29 37 45 Detention time iii-each section (minutes) 1.5.4 .95 .69 .54 .44

fetal detention time, minutes"; l6 7 ramps 0 V tance theplates were set for m mum discharge. adjacent the impeller n a d a n et e ctp e ixing chamber. The total detention time 13 in the mixing zone with this setting was 3.42 minutes, as follows:

Thus adjustment of the valve plates varies the detention time by 50% of the minimum time without possibility of short circuiting in the mixing zone. It is important to note that the hydraulic mixing secured in the mixing chamber permits one to control the detention time of the liquid undergoing treatment, and also to bring the minimum detention time closer to the average, or desired, detention time.

The rolling motion in the mixing chamber, heretofore described, causes the heavier particles in the slurry settling on the floor to collect along the longitudinal ridge Ila. Thus the solids are automatically concentrated along the ridge Ila and are withdrawn through the outlet 56 as desired.

It will be obvious that the apparatus of my invention can take many forms. For example, in some flocculation processes the use of a reagent is not necessary, and it will be obvious that in such cases the chemical inlets can be eliminated. It is also obvious that the form of the pressure chamber can vary over a considerable variety of forms, and that the valve plates 81 and 88 can be operated in a variety of manners to secure the desired results. Such things will be understood by those skilled in the art, and need not be shown in detail.

I claim:

1. A coagulating device comprising a tank, partition means dividing said tank into a lower reaction chamber in the lower portion of said tank and a superposed pressure chamber, said partition means being so constructed and arranged as to provide open passageways between said chambers at the side of said tank inlet means for introducing liquid to be treated and any treating reagent into one end of the reaction chamber, an outlet from the horizontally opposed end of the reaction chamber discharging into the pressure chamber, a pumping means positioned to pump liquid through said outlet, and outlet means for coagulated liquid functionally remote from said inlet means, said passageways discharging tangentially to the flow from said liquid inlet to said outlet from the reaction chamber.

2. Liquid treating apparatus comprising an elongated tank, a treated liquid outlet from the upper part of said tank, means for introducing a treating reagent to the liquid to be treated at a point functionally remote from said treated liquid outlet, a solids outlet from the lower portion of said tank, a partition structure within said tank forming therein a longitudinally extending hood in the lower portion thereof, a partition inside the hood and dividing the space under the hood into an upper pressure chamber and a lower mixing chamber, said chambers extending the length of the hood, valved conduit means leading from the pressure chamber and discharging downwardly over the upper side of the hood, and passageways opening from the pressure chamber into-the mixing chamber and located inside and adjacent the sides of the hood throughout the length thereof, characterized by flow passages leading from the mixing chamber to the pressure chamber at each end thereof, mechanically driven liquid moving members so positioned as to pump liquid through each of said flow passages from the mixing chamber into the pressure chamber, an inlet for liquid to be treated discharging transversely into the mixing chamber at a point approximately midway between said flow passages, and a valve plate for each passageway, said valve plates being pivoted with respect to said passageways in such manner as to provide trapezoidal openings of variable width through said passageways.

3. Liquid treating apparatus comprising a basin, partition means forming a longitudinally extending mixing chamber in the lower portion of said basin and a superposed pressure cham-.

her, an outlet leading from said pressure chamber and discharging downwardly over the partition means, an inlet into said pressure chamber from one end of the mixing chamber, a pumping means for pumping liquid through said inlet, a passageway leading from the pressure chamber into the mixing chamber, valve means for said passageway movable to vary the shape of the opening of said passageway to provide in one position an opening'of uniform. width and in another position a progressively enlarged opening from one end of the passageway to the other. means for introducing liquid to be treated into the end of the mixing chamber opposite said inlet to the pressure chamber, a solids outlet in the lower portion of said basin, and a treated liquid outlet in the upper portion of said basin, said passageway discharging into said mixing chamber tangentially to the flow from its inlet to its outlet.

4. In a liquid treating apparatus a treating chamber, a horizontally extending partition structure within said treating chamber forming therein a longitudinally extending reaction chamber in the lower portion thereof, and a superposed pressure chamber, passageways from the pressure chamber into the reaction chamber discharging tangentially adjacent the sides of the reaction chamber, an outlet leading from the reaction chamber to the pressure chamber at one end of the reaction chamber, a mechanically driven liquid moving member so positioned as to pump liquid through said outlet from the reaction chamber into the pressure chamber, an inlet for liquid to be treated discharging into the reaction chamber at the end of said reaction chamber horizontally opposed to said outlet, an inlet for introducing a treating reagent to the liquid to be treated, valve members operatively connected with said passageways and pivotably mounted, said passageways in one position of said valve members having an opening of uniform width, and in another position of said valve members having a progressively enlarged opening from one end thereof to the other, and an outlet for treated liquid functionally remote from said inlets for liquid and reagent.

5. A liquid treating apparatus comprising a basin, partition means forming a longitudinally extending mixing chamber in the lower portion of said basin, a superposed pressure chamber and a clarification chamber, an outlet from said pressure chamber and discharging downwardly ovrthepartitioii means, inlet meansfor' mimducirigliquid t'o"b e treated into said mixing chambr,'a pa s g w y' from said mixing chain her "tosaidipres'sfur'e chamber, a pumping means piimping liquid through said'passagevvay, return passageways leading fr'om the pressure chamber into' the mining chamber, valve plates regulating flow through said passageways, a solids outlet tifom the lower portion of said basin, and a treated liquidoutle't in the upper portion of said clarification chamber, characterized in that said inletlmelans discharge into one end of said mixchamber, and'said passageway leads from the other end of the mixing chamber opposite slaid inl et means, and said return passageways discharge tangentiallyto the'fiow fromsaid one end of the mixing chamber to the other end thereoff whe'reby a spiraling motion is set up in the liquidih said mixing 'chamber from said one end to the other, "and in that said valve plates arepiv'oted at their centers, whereby inwardmovement of one'en'd'portion of said valve platescauses outward movement of the other end-portion, such movement resulting in valve openings increasing in'width from one end of sai'd'passageways to the other.

6 Liquid 7 treating apparatus comprising an elongated tank, a treated liquid outlet from the upper portion of said'tarihimeans for introducing a treating reagentto the liquid to be treated ata point functionally remote from said treated liquid outlet, a solids outlet from the lower poruse or said tank, a partition structure within said tank'forming thereina longitudinally extending hood in the lower portion thereof, a partition inside the hood and dividing the space under the hood into anupper pressure chamber andfa lower mixing chamber, said chambers extending the length of the hood, a passageway 16 l'eadingfrom the pressure chamber and discharging downwardly over the upper side of the hood, and passageways from the pressure chamber into the mixing chamber located inside and adjacent the sides of the hood throughout the length thereof, characterized by an outlet leading from the mixing chamber to the pressure chamber at one end thereof, a mechanically driven liquid moving member so positioned as to pump liquid through said outlet from the mixing chamber to the pressure chamber, an inlet for liquid to be treated discharging transversely into the mixing chamber at the end opposite said liquid moving member, a valve member for each of said last mentioned passageways, each valve member being pivoted at a central point thereof and providing an adjustable opening for its passageway which is of uniform width in one positionof said valve member and, in another position of said valve member, is progressively enlarged from one end of said-passageway to its other end.

WALTER J. HUGHES.

References Cited in the file of this patent UNITED STATES PATENTS Number I Name Date 1,030,366 Winters June 25, 1912 2,245,587 Hughes June 17, 1941 2,245,588 Hughes June 17, 1941 2,264,139 Montgomeryet a1. NOV. 25, 1941 2,348,122 Green May 2, 1944 2,348,123 Green 'et al. May 2,1944 2,355,069 Green Aug. 8, 1944 2,391,738 Prager Dec. 25,1945 2,427,886 Walker Sept. 23, 1947 2,425,372 Green Aug. 12, 1947 2,509,683 Gre'en May 30, 1950 

1. A COAGULATING DEVICE COMPRISING A TANK PARTITION MEANS DIVIDING SAID TANK INTO A LOWER REACTION CHAMBER IN THE LOWER PORTION OF SAID TANK AND A SUPERPOSED PRESSURE CHAMBER, SAID PARTITION MEANS BEING SO CONSTRUCTED AND ARRANGED AS TO PROVIDE OPEN PASSAGEWAYS BETWEEN SAID CHAMBERS AT THE SIDE OF SAID TANK, INLET MEANS FOR INTRODUCING LIQUID TO BE TREATED AND ANY TREATING REAGENT INTO ONE END OF THE REACTION CHAMBER, AN OUTLET FROM THE HORIZONTALLY OPPOSED END OF THE REACTION CHAMBER DISCHARGING INTO THE PRESSURE CHAMBER, A PUMPING MEANS POSITIONED TO PUMP LIQUID THROUGH SAID OUTLET, AND OUTLET MEANS FOR COAGULATED LIQUID FUNCTIONALLY REMOTE FROM SAID INLET MEANS, SAID PASSAGEWAYS DISCHARGING TANGENTIALLY TO THE FLOW FROM SAID LIQUID INLET TO SAID OUTLET FROM THE REACTION CHAMBER. 